Verification of the psychometric properties of the Japanese version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 15 palliative (EORTCQLQ-C15-PAL)

Abstract

Purpose: We compared Japanese versions of the EORTC QLQ-C15-PAL and QLQ-C30 to assess the utility of the former survey for terminal-phase cancer patients.

Methods: We used QLQ-C30 scores from the survey prior to each patient's death and extracted QLQ-C15-PAL data. We determined intraclass correlation coefficients (ICCs) of the five QLQ-C15-PAL subscales: physical functioning, emotional functioning, fatigue, nausea and vomiting, and global health status/quality of life (QOL) and assessed equivalent-form reliability. Regression analysis was used to determine the extent to which QLQ-C15-PAL items explained the QLQ-C30 score.

Results: Our study included 32 of 91 cancer patients receiving palliative care who could self-administer the questionnaire. The ICC between the QLQ-C15-PAL and QLQ-C30 scores was 0.93 or higher. The proportion of variance (R-squared) for each subscale was 0.87 or higher.

Conclusion: We examined the validity and reliability of the Japanese version of the QLQ-C15-PAL. We found an 87% or higher chance that the QLQ-C15-PAL could explain the original QLQ-C30 score. Therefore, QLQ-C15-PAL appears to be useful for assessing the QOL of terminal-phase cancer patients.